—n. 1. the part of a garment that covers the arm, varying in form and length but commonly tubular.
2. an envelope, usually of paper, for protecting a phonograph record.
3. Mach.a tubular piece, as of metal, fitting over a rod or the like.
4. laugh up or in one's sleeve, to be secretly amused or contemptuous; laugh inwardly: to laugh up one's sleeve at someone's affectations. 5. have something up one's sleeve, to have a secret plan, scheme, opinion, or the like: I could tell by her sly look that she had something up her sleeve.
—v.t. 1. to furnish with sleeves.
2. Mach.to fit with a sleeve; join or fasten by means of a sleeve.